It is known to use brushless motors for certain power tools, including driver drills, because brushless motors are relatively compact and very durable. Such motors include a stator having a plurality (e.g., six) of teeth that protrude radially inwardly. The stator is formed by a plurality of steel plates or laminations, and coils that form different phases are respectively wound around every tooth. The motor also includes a rotor comprising a rotary shaft that passes through the stator and that includes permanent magnets. The motor may also include a discoidal sensor circuit board, which is attached to the stator and has magnetic sensors (Hall effect ICs or the like) that detect the positions of the permanent magnets provided on the rotor.